A system, device and method facilitates maintenance of operations within a body of water, and more particularly provides a system, device, and method for removing a pre-specified amount of sludge from the bottom of a lagoon.
It is a common problem that sludge accumulates at the bottom of lagoons. If this accumulation is allowed to continue, the solids removal efficiency of the lagoon would be diminished and the associated plant could be in violation of its discharge permit. The present approach is to hire a dredging company to completely clean out the lagoon. These companies typically use large floating dredges that can cause a re-suspension of solids in the water column. As mentioned before, this can result in a violation of the discharge permit.
Various cleaning devices are presently available and examples are illustrated in U.S. Pat. Nos. 4,160,632, 4,536,286, 4,677,997, 5,622,571 and 6,237,177.
There is a need in the industry for a device that effectively removes the sludge from the bottom of a lagoon without adversely affecting the solids removal efficiency of the lagoon.
An object of the present invention is to provide a device for removing sludge from a lagoon but it could be used in any water body where removal of sludge or sediment is needed. This includes sewage lagoons, settling basins, stabilization ponds, and recreational lakes, etc.
Another object of the present invention is to provide a device for removing sludge from a lagoon that may be used in an operating lagoon without causing a violation of a discharge permit. More particularly, the device of the present invention may be used without shutting down or taking out of service the lagoon.
Another object is to provide a sludge removal device that is simple to operate and may be operated easily by in-house personnel at their convenience.
Another object is to provide a sludge removal device that, when used as intended, does not require the lagoon to be cleaned because it maintains the amount of sludge at a steady state. In other words, the device of the present invention removes only enough sludge to maintain a steady state, instead of removing all the accumulated sludge.
Another object is to provide a sludge removal device that requires significantly less labor because it is intended to remove only a portion of the sludge on an annual basis. The amount of sludge removed is determined by the annual accumulation rate.
Yet an additional object of the present invention is to provide a sludge removal device that is significantly less expensive to own, operate and maintain.
Another object is to provide a sludge removal device that allows an operator to reverse the direction of travel without having to turn the device around.
Another object is to provide a sludge removal device that includes a tapered grill at both ends thereof to prevent large objects from clogging the device and, at the same time, allow it to slide over obstructions.
Another object is to provide a sludge removal device that includes a surface float system that allows the operator to raise and lower the device anywhere in a lagoon, that supports a 90 degree pipe transition elbow and vertically stabilizes the device during operation.
Another object is to provide a sludge removal device that includes a winch system that allows the operator to control the rate and direction of travel.
Another object is to provide a sludge removal device that includes a pump system that transports the sludge from the device, through a float supported hose, to a remote onshore repository.
In summary, a preferred embodiment of the present invention provides a sludge removal device that removes an amount of the sludge that is equal to its accumulation over a pre-specified period, such as a year, thereby creating a steady state such that a lagoon""s sludge holding capacity is not exceeded. Also, since it only disturbs a small portion of the lagoon, the effluent quality is not significantly diminished. Therefore, the lagoon remains in operation while the sludge is being removed. In addition, since only a small portion of the sludge is removed, only considerably downsized equipment is needed, resulting in significantly less disturbance of the water column.
A preferred embodiment of the present invention provides a sludge removal device having an elongated frame including first and second end portions. The frame includes first and second laterally spaced runners defining a recess therebetween. A scoop is positioned in each end of the recess and the scoops each include an inclined bottom. Both the first and second end portions include an opening, over which a grill is fitted, to permit fluid communication with the sludge. A pump is operably connected to the central pump chamber of the device for pumping the sludge collected in the scoop to a remote location.